Interpretive Summary: This study examines the growth patterns of spring-planted brown mustard, canola and camelina in western Nebraska. This three-year study recorded the time-course growth in canopy size, and the weights of roots, vines, and fruit. The crops were planted in the second week of May and a number of agronomic parameters were evaluated throughout the growing season for each crop. Significant differences were found between the crops in their rate of growth and the final agronomic values. Overall yield was about 1500 kg/ha. Oil in the two Brassica was comprised mostly of C18:1 (over 60%). The major fatty acid in Camelina was C18:3 (30% of the oil). Considering the growth and development of these crops, they would be suited for growing in this area and may produce oil economically when grown under limited water availability.

Technical Abstract:
With increased emphasis for diesel substitution, production of brown mustard (Brassica juncea), canola (B. napus) and camelina (Camelina sativa) used as biodiesel may increase in the High Plains. The objective was to elucidate the growth pattern of these crops when spring-planted in western Nebraska. Field trials were conducted in 2005, 2006 and 2007 with early May planting and in 2007 with a mid-April planting. Plots were seeded 2 cm deep at 200 plants m-2. Four plants were destructively sampled at about 4, 6, 8, 9, and 12 weeks after planting (WAP). Canopy size was field measured. Canopy heights peaked by 9 WAP at 95, 85 and 70 cm for brown mustard, canola and camelina, respectively. Stem length increased to 12 WAP at the rates of 1.24, 1.22 and 0.85 cm/d for brown mustard, canola and camelina, respectively. Root weight accumulated linearly from 4-9 WAP. The Brassica grew roots faster and achieved higher weights than camelina. From 4-6 WAP, vine fresh weight accumulated rapidly for these crops, leveling and then gradually declining as leaves desiccated. Vine dry weight increased to 9 WAP and then plateaued. The maximum vine dry weights, reached at 9 WAP, were 4.3, 4.5 and 3.0 g/plant for brown mustard, canola and camelina, respectively. By 9 WAP, pods were present and accumulated dry matter while leaves senesced. Pod fresh weight reached its peak at 9 WAP while its dry weight increased linearly to 12 WAP at rates of 0.36, 0.24 and 0.096 g/d for brown mustard, canola and camelina, respectively. The 2006 harvest showed no significant difference between crops with a mean yield of about 1500 kg ha-1. Fatty acid composition was dramatically different between the crops, as previously reported. After a delay due to slower emergence, April-seeded plants grew faster than those seeded in May. Brassica pod weight at 12 WAP of April-seeded plants weighed significantly greater than that of May-seeded plants. However, this was not true of camelina for which the rate did not differ between the two plantings. Population densities of 200 and 400 plants m-2 were compared in 2007 and no significant difference was observed. The growth patterns of these crops indicated that all three would be suited for production in the northern High Plains.